Noting that use of atopic disease-causing T cells as therapeutic targets and clinically useful biomarkers is limited by lack of an accepted methodology to identify and differentiate these cells from nonpathogenic TH2 cell types, Erik Wambre, Ph.D., from the Benaroya Research Institute in Seattle, and colleagues present data on a subset of human memory TH2 cells confined to atopic individuals that included all allergen-specific TH2 cells.

The researchers found that the subset of cells was made up of terminally differentiated CD4+ T cells, which were characterized by coexpression of CRTH2, CD49d, and CD161; they also exhibited functional attributes that were distinct from conventional TH2 cells. Cells with this allergic disease-related phenotype were designated as the TH2A cell subset. In transcriptome analysis, a distinct pathway was identified in the initiation of pathogenic responses to allergen; elimination of these cells indicated immunotherapy-induced clinical responses.

"Together, these findings identify a human TH2 cell signature in allergic diseases that could be used for response-monitoring and designing appropriate immunomodulatory strategies," the authors write.

Two authors are listed as inventors on patents held or submitted by the Benaroya Research Institute.